Method of extruding long seamless tubing



April 28, 1931. F. SINGER 1,802,785

METHOD OF EXTRUDING LONG SEAMLESS TUBING ,Filed Oct. 11, 1924 [nare/afar Ml/1M1 q'il orlwy l5 given onl PM 2a, 1931 UNITED sTATasPATENT, orrlca FRITZ SINGER, 10]! NUREL IBERG, GERMANY mnon OIEI'I'IBUDING LONG SEAILEBS TUBING Application filed October 11, 1924.swarm). viam.

The present'invention relates to an imroved heat extrusion process, forthe prosuction of seamless tubes of perforated or imperforated billetsof copper, zinc, alumi- 5 num and other metals and alloyswhich can beextruded above 300 C. and below 900 C. In the manufacture of thesetubes, the problem is to extrude large amounts of metals in a plasticcondition through the -shaped opening between the mandrel 'an the die.

Heretofore, in heat extrusion of tubes the pressing surface of the punchhas'always been made flat and the surface of the die a slight bevel orinclination at most. It as now been found that the bevel an 1e of thedie surface exerts considerable inguence on the result, and that a bevelangle of about 27, with a permissible deviation of a few degrees aboveand below, is the best and that greater deviations from this angleresults in defects such, for example, as

'doublin in the last extruded portions of the tube. 'l hese defectsdonot arise in heat ex truded pipes in hydraulic. presses, as aconsiderable press residue remains in the receiver.

In hydraulic heat extrusion idue amounts to -45% of the ingot, while itis possible with crank press to reduce it to This result is to beascribed on the one hand A to the great increase of the of the stroke,and on the ot formation of the the press resweight of the 0 the use of aer to the inclined operative surfaces of the punch and the die, whichpermit the remainder of the ingot to flow out uniformly.

Referring now to the drawings in which like reference charactersindicate correspondin parts throughout:

igure 1 is a vertical longitudinal section through the extrusion tool,wherein the full lines show the position of the press punch at thebeginning of the extrusion and the dotted lines the position thereof ontermination of the perforating step,

Fig. 2 is a similar section through the extruding tool, showing thepress punch in its lowermost position and the extruded tube,

Fig. 3 1s a longitudinal section through a 23% thereof.

ressure at the end" metal ingot, which is partially (fiorlguiding theperforating punc or manre Fig. 4 is a longitudinal section through ametal ingot provided with a perforation through its entire length.

On top of the apertured bed-plate'of an upright crank press (not shownon the drawing) the apertured base-plate g, the container 41 and thematrix die f are mounted together. The matrix die rests with thecontainer on said base-plate and is surrounded by the container. The dieI has a bore f which corresponds to the outer diameter of the finishedtube and extends into a large-bore.

The conical face of the matrix die bearing the billet forms an angle ofabout 30 with the horizontal plane.

he punch a isn'iounted on the reciprocating member "of'the crank ress(not shown in the figures) and provide at its lower end with an annularremforcementb. The end of the pouch is turned off on a bevel to agreeaccurately with the face ofthe matrix die.

e perforating mandrel a is attached to the punch. The billet h or'h isadapted to inserted in the container. The billet I1. 18 partially, thebillet h totally bored, the partial-hole l or the complete bore 1' beingadapted to guide the mandrel.

The process is carried out inthe following manner:

The billet of metal to be extruded is heated to a suitable temperatureand is then inserted in the container"; The punch and mandrel which havebeen heated by a gas flame and coated with a friction material such as amixture of oil and graphite will now descend and the mandrel will enterthe hole I or the bore depending upon the type of billet used. If thebillet h is used the mandrel will be forced through the billet and intoand through the die. This will cause the metal to ascend as indicated bythe dotted lines h and a portion of the metal will be forced through thedie ahead of the mandrel as a plug m before the extrusion of the tubebegins. As soon as the punch contacts with the metal so that the metalcan no longer ascend, it will be extruded through the anrforated nularopenin between the die and the mandrel, to there y form the tube iasshown in Fig. 2.

The entireu quantity of metal making up 5 the billetlis extruded as atube with the exception of the-plugm' and the thin-flared residue is,which is connected with the tube. In order to remove the tube from thetool the residue is is cut 0E along the edge of the tube by means of acircular chiseh'whereupon the tube drops down, the residue. adhering tothe chisel with" which it is removed. -1 The; working temperatures mostsuitable -for the several metals and alloys are easily ascertained. Foraluminium they are between 350fland 4509 0., for brass alloys bew-tween65 0 and SOOS G. and for copper between 800 and 900 C. s

slz la m;as yinve o a V The method;of xtruding a longseamless ;tulpefrom ;a-large;block oi -metal oi greater r ;,-.length than-diameter,comprising heating- -;the;block=,toay temperature of not less thanabout; 350?; 1C andwhile-in a-container ap- ,;.,ply ing-,pressure:to,the thus-heated block in {t the directionfofi: its-length betweenrelatively- 11 moving ;member s haying concentric conical a oppo nglockengagi g ur a es inc i a ijgapprogrimatel 60,? to the center line,of said pressure, thereby extruding allbut a small residue, isaidblockas along seamless tube i ot uniformphysical characteristicsthroughi .ln testimony whereof ,I afiixm signature.

: r 5 c FRITZ ;INGER.

